Some questions about network connection in openstack VM

May anyone hear about cloudlet or openstack++? That is a VM platform based on the openstack kilo developed by CMU. And I encountered a difficulty about network connection in this.
My VM cannot be accessed from another physical machine(test by apache2), but the VM had network connection indeed. I can executed the commands Like apt-get update and upgrade in my VM.
What I think maybe wrong is floating-ip. When I did not associate the floating-ip, the VM network connection is well. As I associated the floating-ip, the VM became disconnection. Should I associate an IP address that is not being used?
There are the commands I used to create network: